Here's his official translated bio from Play Nintendo's website
Wario’s partner. An eccentric character who thinks Luigi is his rival. He has a smug, sly and rebellious personality. In order to build up strength to battle with Mario and Luigi, it seems he has (up until now) been working hard at a secluded location. Is he actually a nice, hardworking person!
Because his limbs are long, he can do very well in sports where he can use this to his advantage. However, because his posture is always bad, he doesn’t seem to look very strong…
By the way, even though Wario is often with [Waluigi], the two don't seem to be brothers!
Interestingly enough, the "smug, sly and rebellious personality" should actually translate to "conceited, sly, and twisted personality" since that is more similar to the original meaning of the kanji itself. Also the, "Is he actually a nice, hardworking person!", seems a bit confusing. The nice is supposed to be used like "pretty" instead of "kind-hearted" so it might throw people off.
Other than that this translation is fine.